A plastic optical fiber is flexible and does not break, and thus it is superior in handling property as compared with a glass fiber and suitable for wiring between equipments or wiring inside equipments.
As a mode of using a plastic optical fiber, Patent Document 1 discloses an optical fiber ribbon having the structure shown in FIG. 3. This optical fiber ribbon is one wherein a plastic optical fiber 51 is covered with a reinforcing layer 52 and further covered with a resin layer 53 such as a color coat layer to form a plastic optical fiber 54, four of which are arranged in parallel to have a collective coating 55 applied to obtain an optical fiber ribbon 56.
Further, as shown in FIG. 4, an optical fiber ribbon in which a collective coating is thinly formed has also been put on the market. In the FIG., reference numeral 61 denotes a plastic optical fiber, 62 a reinforcing layer, 63 a plastic optical fiber, and 64 a collective coating.